#include<iostream>
#include<vector>
using namespace std;

int singleNumber(vector<int>& nums) 
{
    int a = nums[0];
    for (int i = 1; i < nums.size(); ++i)
    {
        a ^= nums[i];
    }
    return a;
}


int main()
{
    int a[4] = { 2,2,3,2 };
    vector<int> v(a, a + sizeof(a) / sizeof(int));
    int b = singleNumber(v);
	//cout << 1 ^ 9 << endl;
	//printf("%d", 1 ^ 0);
	return 0;
}